Many social critics wag their fingers at what they perceive to be frivolous luxury spending. But that misses the point that consumption norms are local. It's not just the rich who spend more when they get more money. Everyone else does, too. The mansions of the rich may seem over the top to people in the middle, but the same could be said of middle-class houses as seen by most of the planet's seven billion people.

No one could argue with a straight face that the couples getting married today are much happier just because their wedding celebrations cost three times as much as those in 1980. Bigger mansions and costlier parties are wasteful in the same sense that larger antlers on all bull elk are wasteful. The good news is that simple changes in the tax system can eliminate much of this waste without having to deny people the right to decide for themselves how best to spend their money.

We've long known that firms can pay higher wages if they spend less on workplace safety enhancement. Libertarians ask, "If a worker is willing to accept higher wages in return for his agreement to exercise greater caution while performing his job, why should the government prevent him from making that choice?" It's a rhetorically powerful question, yet it overlooks the fact that the agreement in question will have adverse effects on others.

Unless we can act collectively, there would be no way to defend ourselves, no way to define or enforce property rights. We couldn't curb congestion or pollution or build and maintain public infrastructure.

A good school is a relative concept, and the better schools are located in more expensive neighborhoods. But when everyone bids more for a house in a better school district, they succeed only in bidding up the prices of those houses. As before, 50 percent of all children will attend schools in the bottom half of the school quality distribution. As in the familiar stadium metaphor, all stand, hoping to get a better view, only to discover that no one sees better than if all had remained seated.

As John Maynard Keynes taught us in the 1930s, in such situations, government is the only entity with both the motive and the ability to boost total spending by enough to put people back to work. As it happens there are long lists of important public projects that cry out to be done.

Rising inequality hasn't really accomplished anything of value for its ostensible beneficiaries, the top one percent. They've all built bigger mansions and staged more lavish parties. But in so doing, they've simply raised the bar that defines what's considered adequate in these categories.